Therapeutic gas can be delivered to patients, in need thereof, to provide medical benefits. One such therapeutic gas is nitric oxide (NO) gas that, when inhaled, acts to dilate blood vessels in the lungs, improving oxygenation of the blood and reducing pulmonary hypertension. Because of this, nitric oxide can be provided as a therapeutic gas in the inspiratory breathing gases for patients with pulmonary hypertension.
Many of these patients who may benefit from nitric oxide gas receive breathing gas from a breathing circuit affiliated with a ventilator (e.g., constant flow ventilator, variable flow ventilator, high frequency ventilator, bi-level positive airway pressure ventilator or BiPAP ventilator, etc.). To provide nitric oxide to a patient who receives breathing gas from a ventilator, nitric oxide may be injected into the breathing gas flowing in the breathing circuit. Using this technique the desired dose of the nitric oxide may be based on the concentration of the nitric oxide in the breathing gas, for example, after the nitric oxide has been injected into and/or blending with the breathing gas.
The above, and similar, techniques used to deliver nitric oxide into breathing gas flowing in the breathing circuit can present substantial challenges. For example, providing accurate and/or precise doses of nitric oxide to the patient can be substantially challenging as the breathing gas can have unknown and/or inconsistent flow profiles. This can complicate accurately and/or precisely delivering nitric oxide to the patient at desired doses as it may be substantially difficult to ensure the nitric oxide is delivered at the desired concentration (e.g. set dose). Further, delivering nitric oxide at the desired dose can be substantially important, for example, as dosing can substantially impact safety and efficacy.
Accordingly, a need exists to at least ensure accurate and/or precise dosing of nitric oxide delivered to patient who, for example, may be receiving breathing gas from a breathing circuit affiliated with a ventilator.